Minister denies 'overload'

"I don't think that there is exam overload," she said. "I think that the exams at 16, the GCSEs, are very important in that it's at the end of the compulsory school age and we want children to mark that."

She added that AS levels gave pupils a broad range of subjects and that A-levels acted as a "gateway" to further education. "I think it's important that we do externally validate the learning that takes place."

Ms Hodge told the BBC Radio 4 Today programme that tests "if they are well set ... will ensure that they do test the skills and aptitudes that we want young children to have."

Liberal Democrat education spokesman Phil Willis said there was an obsession with testing. "We're obsessed with testing and measuring, indeed, if that would make children more intelligent then my goodness we'd have the brainiest and best students in the world."

Schoolchildren have to sit more than 100 external examinations between the ages of 5 and 18, he said. "That's not education, that's a system of testing."